In: Mechanical Engineering
6) A tapered surface is to be turned on an automatic lathe. The work piece is 900 mm long with minimum and maximum diameters of 150 mm and 300 mm at opposite ends. The automatic controls on the lathe permit the surface speed to be maintained at a constant value of 200 m/min by adjusting the rotational speed as a function of work piece diameter. Feed=0.25 mm/rev and depth of cut = 3.5 mm. The rough geometry of the piece has already been formed, and this operation will be the final cut. Determine (a) the time required to turn the taper and (b) the rotational speeds at the beginning and end of the cut. (c) Suppose that the automatic lathe surface speed is not available and a conventional lathe must be used. Determine the rotational speed that would be required to complete the job in exactly the same time as in part (a) of the problem.